The present invention relates to a digital copier or similar digital image forming apparatus of the type having a scanner for reading a document, a memory for storing image data generated by the scanner, and a printer for outputing the image data read out of the memory.
Conventional digital copiers include one having a plurality of page memories therein. In this type of copier, as a scanner reads a single document, the resulting image data are written to one or more page memories. Subsequently, the image data are read out of the page memory or memories and transferred to a printer to be printed on a paper. This allows an image to be formed a plurality of times only if the document is read once, thereby promoting a rapid copying operation. However, the problem with the copier having a page memory or page memories is that the memories cannot be used efficiently when they do not match a document in size and orientation. For example, when a copier having a page memory sized to match a document of A4 size and oriented horizontally long reads a document of A4 size and positioned vertically long, two page memories are required. Japanese Patent Publication No. 4-62223 teaches one of the conventional implementations relating to the present invention.